Restricting calories may boost your immune system

Restricted-calorie diets have been shown in some studies to improve longevity and provide other health benefits, but many studies have focused on animals rather than humans.

A new study finds that calorie restriction may bolster the immune system in adults. Researchers from Tufts University randomly placed 46 overweight, but not obese, men and women ages 20 to 40 on one of two diets for six months: one in which calories were reduced 10 percent, and another in which they were reduced 30 percent. All food was supplied to the test subjects.

Participants were tested to see what effect calorie restriction had on their immune system. They were given a delayed-type hypersensitivity test, which can detect allergens, among other things, and is considered a way to check whole-body immune response. Researchers also checked T-cells, a kind of white blood cell, and another immune system marker.

At the end of the six months, DTH response went up in both the 10 percent and the 30 percent calorie-restricted groups compared with the beginning of the study. Both groups also showed improvement in T-cell function.

The study is part of the Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy conducted at the Human Nutrition Research Center on Aging at Tufts. It was published in the Journal of Gerontology: Biological Sciences.